1. Field of the Invention
The present invention relates to an image display apparatus, an image display method, and a computer readable recording medium storing an image display program.
2. Description of Related Art
In recent years, the performance required by various fields in an image display apparatus has increased as informational technology has advanced. Among such image display apparatuses, a liquid crystal display that allows optical characteristics to be changed by the electrical control of the orientation of liquid crystal molecules, that has low power consumption, that is flat-panel shaped, and that does not strain the eyes and the like has become particularly sought after. Furthermore, a projection type of liquid crystal display (liquid crystal projector) in which images emitted from an optical system that uses liquid crystal light valves are transmitted through a projection lens and projected in enlargement on a screen is becoming widely used as one form of liquid crystal display.
In this projection type of liquid crystal display, liquid crystal light valves are used as an imager, however, due to leakage light and stray light, the brightness range (dynamic range) that can be displayed is narrow, and in some cases an improvement in image quality is difficult to achieve. Because of this, the dynamic range control method has been proposed for the improvement of the contrast of the image, which changes the flux of light irradiated into the light valves (imager) in accordance with image signals and expands data representing the brightness level of an image displayed on the light valve. However, if an image displayed on a light valve is expanded, problems occur such as the RGB ratio (balance) of a projected image deteriorating, and the color (i.e., the vividness of the color) of the projected image changing.
The present invention was conceived in view of the above circumstances, and it is an object thereof to provide an image display apparatus, an image display method, and a computer readable recording medium storing an image display program that enables the dynamic range of a displayed image (i.e., the range of displayable brightness) to be altered in accordance with image signals of a displayed image, which are the essence of an image being displayed, without changing the ratios of image signals of a plurality of primary colors.